This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Rpn13 is a proteasome component and newly identified as a ubiquitin receptor. Rpn13 is also the proteasomal receptor for a deubiquitinating enzyme Uch37. These make Rpn13 playing important roles in protein degradation pathway. The function profile of Rpn13 is expected to be elucidated by using modern NMR techniques.